Graham has developed a superb little phono stage to partner the Seven line stage resulting in the Seven preamplifier. This is a new design with many unique features built over a long development timeline is search of the most musically satisfying experience. Like all TRON products it relies on the vacuum tube for amplification. We have kept the stages in the Seven to an absolute minimum and have selected valves/tubes that are musically transparent and rich, but also easily obtainable, giving the potential owner the option of using his or her favourite brand, we can advise here on how this affects the musical performance subtly.
The Seven Pre comes with 4 line level RCA inputs, a phono input for vinyl replay and a tape loop, as well as the mono/stereo switch, mute switch, earth lift switch, silver RCA sockets and non ferrous case like the Seven Phono and Line. Of course this too is made in the UK. It also has fitted a very high quality Elma selector switch and a close tolerance Noble volume control.
The phono stage featured in the Seven Pre is a brand new design and can be ordered as either MM (48dB gain), MC (68dB) or MC high gain for use with low output cartridges, with 74dB gain. This is is configurable at time of ordering.
The Seven Pre’s line stage, being identical to the stand-alone Seven Line, provides up to +15dB of gain. The output stage is a very low impedance high current design, which enables it to be used with any power amplifier, whether transistor or valve. Additional partitioning has been employed internally to help reduce the disruptive effect of magnetic, mechanical and electrical fields for the critical aspects of the circuit. Note: All Sevens can be specified with 20dB, 26dB or a custom MC gain setting at time of ordering.
Inputs: 1 RCA Phono input (L & R) & 4 RCA Line inputs (L & R).
Outputs: 2 RCA main output (L & R) & 1 RCA tape output (L & R).
Valve Complement: 2 × 12AX7 (low noise), 2 × 5687.
Frequency Response: 5Hz–37.5kHz ± 3dB. RIAA within ± 0.5dB
Phono Gain: 48dB – MM. 68dB – MC low gain. 74dB – MC high gain
Line Gain: 15dB.
Output Impedance: <600 Ohms
Mains Supply: 115–240 volts AC (50–60Hz). Earth lift included.
Power Consumption: Nominal 12 watts
Dimensions (mm): 450w × 103h × 335d
Weight: 7kg (net)
Warranty: 2 years (parts and labour)
SEVEN Reference Preamplifier
The Seven Preamplifier stage can be upgraded to the Reference specification to further improve the musical performance from all your musical sources. Graham sources truly unique resistors that in such a simple circuit really bring out a richer and more intimate performance from the artist. We have also upgraded the capacitors to a custom specification to work in harmony with the improved resistors; as in most development activities changing one thing in isolation hardly ever results in a balanced improvement. Graham says “it never ceases to amaze me how improving one component can impact the music in such a significant way, and also how long it takes to find the right combination to retain true harmony.”
SEVEN Ultimate Preamplifier
The Ultimate is the last but one step towards perfection, and involves the use of solid silver wiring throughout the critical signal path. Silver as a conductor has the advantage of a more revealing and transparent reproduction of the music, however care needs to be taken to ensure that this is delivered in a complete and unified manner as sections of silver in a component in isolation rarely provide a benefit. Finding the right dielectric (insulation) for the cables is also critical to extract the best from this expensive material. Graham has redesigned and built a more significant power supply that is unique to audio, which has the effect of making silences darker and dynamic shifts in the music even more dramatic, and with a good recording this is phenomenal. The result is a little like cleaning your windows; you did not necessarily notice they were blocking any light, until afterwards.
Seven GT Preamplifier
The Seven GT is the final step towards analogue perfection in a full function preamplifier, and involves the use of a completely new power supply circuit for all the critical stages. Graham says “this power supply was 5 years in the making and makes a huge improvement in fidelity”, making the Seven GT preamp to one of the most enjoyable amplifiers in the Tron range.